1. Field of the Invention
The present invention relates to a system for detecting obstacles in an intended path ahead of a vehicle and, more particularly, to an obstacle detection system for checking for obstacles in the intended path ahead of the vehicle.
2. Description of Related Art
Obstacle detection devices or systems for automotive vehicles typically include sensors such as scanning type laser radars. Such a laser radar obstacle detection system irradiates laser light ahead of a vehicle and receives reflected laser light in order to detect and check for obstacles in the path of travel ahead. With the obstacle detection system, since scanning can be made over a wide and long range of view so as to detect many objects as obstacles, a judgment of danger can be made for each of the obstacles detected and drive control is appropriately performed. Such an obstacle detection device is known from, for instance, Japanese Patent Publication No. 61-6349.
Because the obstacle detection device described in the above-mentioned publication makes a judgment of danger on an even frequency for all obstacles detected, in spite of the various levels of danger provided by these obstacles, a central processing unit (CPU) of the obstacle detection device must perform a large number of operations for the judgment of danger not only for obstacles producing high danger levels but also for obstacles producing low danger levels. Depending on driving circumstances, the capability of the CPU to practice repetitive operations may be exceeded. In this event, since the danger judgment for each of the many obstacles is retarded, it is potentially impossible to conduct fast response of the drive control system to obstacles of high priority. This leads to failure in escaping from high levels of danger. Although the utilization of a large capability CPU can overcome the problem, it forces the cost of manufacturing the obstacle detection device to go up and, hence, increases the cost of an automotive vehicle. Consequently, there has been a strong demand for an improved obstacle detection device or system capable of being furnished at low cost.